1. Field of the Invention
Example embodiments of the present invention relate to image compression. More particularly, example embodiments of the present invention relate to a method of compressing a 2×2 block based binary image including compressing pixels included in an existing pattern with minimum information and adding color information for pixels having a non-uniform pattern to a bit-stream so as to efficiently prevent degradation of image quality, when the pixels having a repeating pattern and pixels having a non-uniform pattern exist in one block.
2. Description of the Related Art
In a conventional 2×2 block based binary image compression algorithm, image data is compressed using the difference between values of neighboring pixels. Such a 2×2 block based binary image compression algorithm is commonly referred to as Differential Pulse Code Modulation (DPCM).
However, in DPCM, when pixels included in an existing pattern and pixels included in a new pattern exist in one block, information may be damaged during the compression and restoration of an image for all the pixels present in a corresponding block. Such information damage may affect a block which is subsequently compressed.
Thus, when the conventional binary image compression is used, serious visible degradation is generated in blocks having a number of non-uniform patterns and in their neighboring blocks.